• Korean Journal of Crystallography
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• v.11 no.3
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• pp.167-172
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• 2000

CaTiO₃:Pr phosphor thin films were prepared on Si(100), ZnO/glass, Corning glass and ITO/glass by rf magnetron reactive sputtering. The effects of deposition parameters such as oxygen partial pressure, substrate temperature, and annealing conditions on crystallinity and compositional variation of the films were investigated. PL spectra of CaTiO₃:Pr phosphor thin films exhibited red regime peaking at 613 nm and enhanced PL intensity was observed for the film annealed in vacuum atmosphere as compared to the deposit annealed in N₂ environment.

• Journal of the Korean Magnetic Resonance Society
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• v.24 no.2
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• pp.53-58
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• 2020

Free radicals including reactive oxygen species (ROS) are important chemicals in the research area of biology, pharmaceutical, medical, and environmental science as well as human health risk assessment as they are highly involved in diverse metabolism and toxicity mechanisms through chemical reactions with various components of living bodies. Electron spin resonance (ESR) spectroscopy is a powerful tool for detecting and quantifying those radicals in biological environments. In this work we observed the ESR signal of 2,2,6,6-Tetra-methyl piperidine 1-oxyl (TEMPO) in aqueous solution at various concentrations to estimate the uncertainty factors arising from the experimental conditions and signal treatment methods. As the sample position highly influences the signal intensity, dual ESR tube geometry (consists of a detachable sample tube and a position fixed external tube) was adopted. This type of measurement geometry allowed to get the relative uncertainty of signal intensity lower than 1% when triple measurements are averaged. Linear dependence of signal intensity on the TEMPO concentration, which is required for the quantification of unknown sample, could be obtained over a concentration range of ~10³ by optimizing the signal treatment method depending on the concentration range.

• Journal of the Korean institute of surface engineering
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• v.38 no.2
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• pp.73-78
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• 2005

A real-time monitoring of ICP(inductively coupled plasma) assisted magnetron sputtering of MgO was carried out using a QMS(quadrupole mass spectrometer), an OES(optical emission spectrometer), and a digital oscilloscope with a high voltage probe and a current monitor. At the time of ICP ignition, the most distinct impurity was OH emission (308.9 nm) which was dissociated from water molecules. For reactive deposition oxygen was added to Ar and the OH emission intensity was reduced abruptly When the discharge voltage was regulated by a PID controller from 240V(metallic mode) to 120V(oxide mode), the emission intensity from Mg (285.2 nm) changed proportionally to the discharge voltage, but the intensity of Ar I(811.6 nm) was constant. At 100V of discharge voltage, Mg sputtering was almost stopped. Emissions from Ar I(420.1 nm) and Mg I were dropped down to 1/10, but Ar I(811.6 nm) didn't change. And the emission from atomic oxygen (O I, 777.3 nm) was increased to 10 times. These results are compatible with those from QMS study.

• Applied Science and Convergence Technology
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• v.26 no.5
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• pp.118-128
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• 2017

The scope of this work is to determine and compare the effect of electron temperature ($T_e$) and number density ($N_e$) on the yield rate and concentration of reactive chemical species ($^{\bullet}OH$, $H_2O_2$ and $O_3$) in an argon, air and oxygen injected negative DC (0-4 kV) capillary discharge with water flow(0.1 L/min). The discharge was created between tungsten pin-to pin electrodes (${\Phi}=0.5mm$) separated by a variable distance (1-2 mm) in a quartz capillary tube (2 mm inner diameter, 4 mm outer diameter), with various gas injection rates (100-800 sccm). Optical emission spectroscopy (OES) of the hydrogen Balmer lines was carried out to investigate the line shapes and intensities as functions of the discharge parameters such as the type of gas, gas injection rate and inter electrode gap distances. The intensity ratio method was used to calculate $T_e$ and Stark broadening of Balmer ${\beta}$ lines was adopted to determine $N_e$. The effects of $T_e$ and $N_e$ on the reactive chemical species formation were evaluated and presented. The enhancement in yield rate of reactive chemical species was revealed at the higher electron temperature, higher gas injection rates, higher discharge power and larger inter-electrode gap. The discharge with oxygen injection was the most effective one for increasing the reactive chemical species concentration. The formation of reactive chemical species was shown more directly related to $T_e$ than $N_e$ in a flowing water gas injected negative DC capillary discharge.

• Journal of the Ergonomics Society of Korea
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• v.29 no.4
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• pp.585-593
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• 2010

Recently, we designed an interactive virtual space for the multi-purpose hall in Songdo Future City, located in Incheon, Korea. The goal of the design is to make a virtual space that is flexible and can be adjusted thanks to its unfixed seats in order to accommodate different and unspecified audience sizes. Virtual images are interactively adjusted according to the distance, position and size of audiences, information about which is detected by 9 photo sensors. To increase the sense of immersion, intensity and reality, we utilized the technology of scent display that can create appropriate scents to match the images on the screen. The intensity and persistence of scents were determined by the size, distance and position of audiences. The virtual image contains background images and reactive images. The background images repeatedly project images of spring, summer, autumn and winter. The reactive images consist of small portraits or pictures or icons that define or characterize the season types, and these are added to the background image according to the distance, position and size of the audiences.

• Journal of Korean Society of Environmental Engineers
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• v.22 no.4
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• pp.619-627
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• 2000

Biodegradation of the C. I. Reactive Blue 114 was investigated in an upflow anaerobic sludge blanket (UASB) reactor. Important parameters studied include dye concentration, the kind and concentration of carbon source, hydraulic retention time (HRT), and influent pH. Glucose was found to be a better co-substrate than the mixture of volatile fatty acids (VFAs), although its concentration did not affect dye removal efficiency in the range of $1000{\sim}3000mg/{\ell}$. When HRT increased from 6 hr to 24 hr, dye removal efficiency increased up to 12 hr and remained almost constant thereafter at about 40%. When influent pH was varied in the range of 6.0~8.0, the effluent pH was varied in the range of 6.8~7.5 with maximum efficiency at pH 7.0. The highest dye removal rate obtained was $52mg/{\ell}{\cdot}day$, while the maximum dye load to meet the discharge limit of color intensity was estimated to be $46mg/{\ell}{\cdot}day$ at HRT of 12 hr and an influent glucose concentration of $2200mg/{\ell}$.

• Radiation Oncology Journal
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• v.32 no.3
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• pp.103-115
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• 2014

To summarize current knowledge regarding mechanisms of radiation-induced normal tissue injury and medical countermeasures available to reduce its severity. Advances in radiation delivery using megavoltage and intensity-modulated radiation therapy have permitted delivery of higher doses of radiation to well-defined tumor target tissues. Injury to critical normal tissues and organs, however, poses substantial risks in the curative treatment of cancers, especially when radiation is administered in combination with chemotherapy. The principal pathogenesis is initiated by depletion of tissue stem cells and progenitor cells and damage to vascular endothelial microvessels. Emerging concepts of radiation-induced normal tissue toxicity suggest that the recovery and repopulation of stromal stem cells remain chronically impaired by long-lived free radicals, reactive oxygen species, and pro-inflammatory cytokines/chemokines resulting in progressive damage after radiation exposure. Better understanding the mechanisms mediating interactions among excessive generation of reactive oxygen species, production of pro-inflammatory cytokines and activated macrophages, and role of bone marrow-derived progenitor and stem cells may provide novel insight on the pathogenesis of radiation-induced injury of tissues. Further understanding the molecular signaling pathways of cytokines and chemokines would reveal novel targets for protecting or mitigating radiation injury of tissues and organs.

• Journal of Korean Dental Science
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• v.13 no.1
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• pp.35-41
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• 2020

Irritation fibroma is a reactive hyperplastic lesion caused by chronic stimuli with low intensity in the oral cavity. Irritation fibroma is common in middle-aged females but it may also occur at any age and sex. Clinical characteristics of irritation fibroma are similar to other reactive lesions or benign tumors, therefore, histological examination is essential to make an accurate diagnosis. This case report presents two cases of irritation fibroma occurred on the gingiva in young males. Two male patients in their 20s and 30s of age visited the clinic for the evaluation and treatment of painless gingival overgrowth in the anterior region. Clinically, the lesions were well-defined and firm, with similar color and texture to the adjacent normal gingiva. Excisional biopsy under local anesthesia was conducted with a scalpel, and the lesions were completely removed. Histopathologically, connective tissue consisting of dense collagen bundles, proliferation of fibroblasts and minor infiltrated inflammatory cells were observed. Based on the clinical and histopathological findings, the diagnosis of irritation fibroma was confirmed in both cases.

• Toxicological Research
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• v.18 no.3
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• pp.215-226
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• 2002

Acute or repeated physical exercise affects a large number of physiological parameters including hemodynamics, respiration, pH, temperature, gastrointestinal function and biotransformation, which determine the pharmacokinetics of drugs and chemicals. The rate and the amount of a chemical reaching the active site are altered by physical exercise, which results in significant changes in pharmacolosical/toxicological activity of the chemical. This aspect of physical exercise has vast implication in therapeutics and in safety evaluation, particularly for chemicals that have a low margin of safety. However there appears to be a wide inter- and intraindividual variation in the effects of physical exercise depend-ing on the duration, intensity and type of exercise, and also on the properties of each chemical. It is suggested that more studies need to be done to determine which factor(s) plays a major role in the disposition of chemicals in human/animals performing physical exercise. Certain chemicals induce severe toxicity due to metabolic conversion to reactive intermediate metabolites. it is suggested that repeated exercise may enhance the free radical scavenging system by increasing the activity of antioxidant enzymes. This area of research remain to be explored to elucidate the interaction of exercise and chemical on the antioxidant system.

• Journal of the Korean Ceramic Society
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• v.32 no.8
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• pp.950-956
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• 1995

Y2O3 thin films were deposited by reactive sputtering of Y target in Ar and O2 gas mixture. Residual stress was measrued by sin2$\psi$ method of x-ray diffraction (XRD) and growth orientation was examined by measuring the relative intensity of (400) plane and (222) plane of Y2O3 films. In the case that Y2O3 films were deposited at 40$0^{\circ}C$ and at low working pressure below 0.05 torr the film had large compressive stress and (111) plane orientation. At working pressure of about 0.10 torr the film had small compressive stress and (100) orientation. Above working pressure of 0.20 torr, the films had nearly zero stress and random orientation. In the case that the (111) oriented film deposited at low working pressure below 0.05 torr, as substrate temperature decreased, (111) orientation increased. In the case the film, with (100) orientation, deposited at working pressure of about 0.10 torr, (100) orientation increased with decresing substrate temperature. These relationship of residual stress and growth orientation can be explained by the relationship of surface energy and strain energy.